A number of radiation therapies have been developed over the years for treating various diseased tissues, such as cancerous tissues. Significant efforts have been devoted to improving radiation therapies by increasing the accuracy and precision of delivered radiation, thereby limiting damage to neighboring healthy tissue. SRS and SBRT, for example, are advanced therapies employing many precisely focused radiation beams to treat tumors and various abnormalities in the brain, neck and other regions of the body. Each radiation beam has very little effect on the tissue the beam passes through. However, when the beams are collectively focused at a common point or area, the radiation dosage is sufficient to destroy or damage the diseased tissue.
Several SRS machines of differing construction and radiation source are currently available. Photon beam or linear accelerator (LINAC) machines use a single X-ray source for treating diseased brain and/or body tissue. Proton beam or heavy charged particle radiosurgery is another single source device. Access to proton beam radiosurgery is generally limited due to extreme costs associated with building and installation of proton beam apparatus. Alternatively, multi-source devices are also available. Gamma Knife® apparatus, for example, employs multiple (e.g. up to 201) individual gamma ray sources compartmentalized at uniform radial positions in a conical or hemispherical source body. A collimator body is positioned within the source body to direct the gamma ray beams to a common focal point in the patient's brain or body. Moreover, the source body is arranged in a shielding body to preclude radiation exposure to the external environment. Shielding apparatus is generally very large and bulky, often weighing up to 20 tons. Such weight complicates installation of Gamma Knife® apparatus and can require updates to facility infrastructure to ensure proper load support. Additionally, shielding apparatus requires the patient be moved into a closed cylindrical treatment chamber, which can cause discomfort for patients suffering from claustrophobia.